Graham Womack, who used to send stuff to FKAHBT, has a poll open where you can vote on your 25 best players not in the Hall. Voting details are at that link.
Ignoring the issue of steroids, Simba, per the mug, comes to my mind.
And, while not quite as good as Simmons, Bill Madlock wasn’t bad.
And, with the match to gasoline of the Mad Hungarian, Al Hrabosky, that provides the excuse for this classic fight video: